"Common Knowledge": No, Underdog wasn't a Jay Ward production, though it's understandable that some make that assumption, given the similar design aesthetic as Rocky and Bullwinkle. Not helping the fact is that both Jay Ward and Total Television used Gamma Production to animate their shows, contributing to the similar styles.
Fair for Its Day: The Go Go Gophers segments feature very obvious Native American stereotypes that wouldn't fly in this day and age, but at the same time the Gopher Indians were still treated as the heroes, and always outsmarted the U.S. army soldiers and settlers trying to take their land and move them out of their home, something unheard of for an old west series made in the 1960's.
Fridge Brilliance: In the "Commander McBragg" cartoons you can tell he's making up his stories because he looks the same in all his flashbacks as he does when he's telling his story. He would've been years younger had they'd really happened.
Iron Woobie: Underdog's civilian incognito, Shoeshine Boy, lives up to his "humble and lovable" persona. He's extremely polite to everyone, even the villains. As a result, he gets constantly beat up on by Simon and Riff. But since he does not want to reveal his true identity, he takes every hit. Awww...
Values Dissonance: Underdog's powers come from a "Super Energy Pill". It's unlikely a show would depict a character obtaining superpowers in such a manner these days.
Ho Yay: "That time when I met that cute poodle and.. it turned out to be a guy."
So Okay, It's Average: Really it's a kids movie and a live action adaptation at that. Only reason it bombed was basic lack of interest due to these factors. On its own, it's an alright little romp with a few chuckles. And at the least it keeps the basic gist of the cartoon better than, say, Inspector Gadget.